Planetary gear train of automatic transmission for vehicle

Abstract

Nine forward speeds and one reverse speed are achieved by a planetary gear train of an automatic transmission that includes a main shifting portion having three planetary gear sets arranged on an input shaft, an auxiliary shifting portion having one planetary gear set arranged on an output shaft, ten shafts respectively connected with corresponding rotational elements of the four planetary gear sets, and two transfer gears respectively forming external gear-engagement between the main and auxiliary shifting portions.

What is claimed is: 
     
       1. A planetary gear train of an automatic transmission for a vehicle, the planetary gear train comprising:
 a first planetary gear set having first, second, and third rotational elements; 
 a second planetary gear set having fourth, fifth, and sixth rotational elements; 
 a third planetary gear set having seventh, eighth, and ninth rotational elements; 
 a fourth planetary gear set having tenth, eleventh, and twelfth rotational elements; 
 a first externally-engaged gear set having thirteenth and fourteenth rotational elements; 
 a second externally-engaged gear set having fifteenth and sixteenth rotational elements; 
 an input shaft disposed coaxial with the first, second, and third planetary gear sets; and 
 an output shaft disposed in parallel with the input shaft and coaxial with the fourth planetary gear set; 
 wherein the first rotational element and the seventh rotational element are connected with the tenth rotational element through the second externally-engaged gear set, 
 the second rotational element is fixedly connected with the input shaft, 
 the twelfth rotational element is selectively connected with a transmission housing, and 
 the third rotational element is selectively externally-engaged with the eleventh rotational element that is fixedly connected with the output shaft. 
 
     
     
       2. The planetary gear train of  claim 1 , further comprising:
 a first shaft fixedly connected with the first rotational element and the seventh rotational element; 
 a second shaft fixedly connected with the second rotational element, the fifth rotational element, and the input shaft; 
 a third shaft fixedly connected with the third rotational element and the thirteenth rotational element; 
 a fourth shaft fixedly connected with the fourth rotational element and fixedly connected with the transmission housing; 
 a fifth shaft fixedly connected with the sixth rotational element; 
 a sixth shaft fixedly connected with the eighth rotational element and selectively connected with the fifth shaft; 
 a seventh shaft fixedly connected with the ninth rotational element, and selectively connected with the fifth shaft and the transmission housing; 
 an eighth shaft fixedly connected with the tenth rotational element and externally gear-meshed with the first shaft; 
 a ninth shaft fixedly connected with the eleventh rotational element, selectively externally-engaged with the third shaft, and fixedly connected with the output shaft; and 
 a tenth shaft fixedly connected with the twelfth rotational element and selectively connected with the transmission housing. 
 
     
     
       3. The planetary gear train of  claim 2 , wherein two shafts selected from the first shaft, the sixth shaft, and the seventh shaft are selectively interconnected, such that the third planetary gear set integrally rotates when the selected two shafts are connectedly operated. 
     
     
       4. The planetary gear train of  claim 3 , further comprising:
 a first clutch arranged between the second shaft and the seventh shaft; 
 a second clutch arranged between the first shaft and the sixth shaft; 
 a third clutch arranged between the ninth shaft and the fourteenth rotational element; 
 a fourth clutch arranged between the fifth shaft and the sixth shaft; 
 a first brake arranged between the seventh shaft and the transmission housing; and 
 a second brake arranged between the tenth shaft and the transmission housing. 
 
     
     
       5. The planetary gear train of  claim 3 , further comprising:
 a first clutch arranged between the second shaft and the seventh shaft; 
 a second clutch arranged between the first shaft and the seventh shaft; 
 a third clutch arranged between the ninth shaft and the fourteenth rotational element; 
 a fourth clutch arranged between the fifth shaft and the sixth shaft; 
 a first brake arranged between the seventh shaft and the transmission housing; and 
 a second brake arranged between the tenth shaft and the transmission housing. 
 
     
     
       6. The planetary gear train of  claim 3 , further comprising:
 a first clutch arranged between the second shaft and the seventh shaft; 
 a second clutch arranged between the sixth shaft and the seventh shaft; 
 a third clutch arranged between the ninth shaft and the fourteenth rotational element; 
 a fourth clutch arranged between the fifth shaft and the sixth shaft; 
 a first brake arranged between the seventh shaft and the transmission housing; and 
 a second brake arranged between the tenth shaft and the transmission housing. 
 
     
     
       7. The planetary gear train of  claim 3 , further comprising:
 a first clutch arranged between the second shaft and the seventh shaft; 
 a second clutch arranged between the first shaft and the sixth shaft; 
 a third clutch arranged between the third shaft and the thirteenth rotational element; 
 a fourth clutch arranged between the fifth shaft and the sixth shaft; 
 a first brake arranged between the seventh shaft and the transmission housing; and 
 a second brake arranged between the tenth shaft and the transmission housing. 
 
     
     
       8. The planetary gear train of  claim 3 , further comprising:
 a first clutch arranged between the second shaft and the seventh shaft; 
 a second clutch arranged between the first shaft and the seventh shaft; 
 a third clutch arranged between the third shaft and the thirteenth rotational element; 
 a fourth clutch arranged between the fifth shaft and the sixth shaft; 
 a first brake arranged between the seventh shaft and the transmission housing; and 
 a second brake arranged between the tenth shaft and the transmission housing. 
 
     
     
       9. The planetary gear train of  claim 3 , further comprising:
 a first clutch arranged between the second shaft and the seventh shaft; 
 a second clutch arranged between the sixth shaft and the seventh shaft; 
 a third clutch arranged between the third shaft and thirteenth rotational element; 
 a fourth clutch arranged between the fifth shaft and the sixth shaft; 
 a first brake arranged between the seventh shaft and the transmission housing; and 
 a second brake arranged between the tenth shaft and the transmission housing. 
 
     
     
       10. The planetary gear train of  claim 1 , wherein:
 the first planetary gear set is a single pinion planetary gear set and includes a first sun gear as the first rotational element, a first planet carrier as the second rotational element, and a first ring gear as the third rotational element; 
 the second planetary gear set is a double pinion planetary gear set and includes a second sun gear as the fourth rotational element, a second planet carrier as the fifth rotational element, and a second ring gear as the sixth rotational element; 
 the third planetary gear set is a double pinion planetary gear set and includes a third sun gear as the seventh rotational element, a third planet carrier as the eighth rotational element, and a third ring gear as the ninth rotational element; and 
 the fourth planetary gear set is a single pinion planetary gear set and includes a fourth sun gear as the tenth rotational element, a fourth planet carrier as the eleventh rotational element, and a fourth ring gear as the twelfth rotational element. 
 
     
     
       11. A planetary gear train of an automatic transmission for a vehicle, the planetary gear train comprising:
 a first planetary gear set having first, second, and third rotational elements; 
 a second planetary gear set having fourth, fifth, and sixth rotational elements; 
 a third planetary gear set having seventh, eighth, and ninth rotational elements; 
 a fourth planetary gear set having tenth, eleventh, and twelfth rotational elements; 
 an input shaft mounted with the first, second, and third planetary gear sets on an external circumference of the input shaft; and 
 an output shaft disposed in parallel with the input shaft and mounted with the fourth planetary gear set on an external circumference of the output shaft, 
 wherein the first rotational element is fixedly connected with the seventh rotational element, 
 the second rotational element is fixedly connected with the sixth rotational element and fixedly connected with the input shaft, 
 the fourth rotational element is fixedly connected with a transmission housing, 
 the eighth rotational element is selectively connected with the sixth rotational element, 
 the ninth rotational element is selectively connected with the fifth rotational element and the transmission housing, 
 the tenth rotational element is externally gear-meshed with the seventh rotational element, 
 the eleventh rotational element is fixedly connected with the output shaft and selectively externally-engaged with the third rotational element, 
 the twelfth rotational element is selectively connected with the transmission housing, and 
 two transfer gears are respectively arranged between the third and eleventh rotational elements and between the seventh and tenth rotational elements. 
 
     
     
       12. The planetary gear train of  claim 11 , wherein two rotational elements selected from the seventh, eighth, and ninth rotational elements are selectively interconnected, such that the third planetary gear set integrally rotates when the selected two rotational elements are engaged. 
     
     
       13. The planetary gear train of  claim 12 , wherein the two transfer gears comprises:
 a first transfer gear including:
 a thirteenth rotational element fixedly connected with the third rotational element, and 
 a fourteenth rotational element selectively connected with the eleventh rotational element; and 
 
 a second transfer gear including:
 a fifteenth rotational element fixedly connected with the seventh rotational element, and 
 a sixteenth rotational element fixedly connected with the tenth rotational element. 
 
 
     
     
       14. The planetary gear train of  claim 12 , wherein the two transfer gears comprises:
 a first transfer gear including:
 a thirteenth rotational element selectively connected with the third rotational element, and 
 a fourteenth rotational element fixedly connected with the eleventh rotational element; and 
 
 a second transfer gear including:
 a fifteenth rotational element fixedly connected with the seventh rotational element, and 
 a sixteenth rotational element fixedly connected with the tenth rotational element. 
 
 
     
     
       15. The planetary gear train of  claim 13 , further comprising:
 a first clutch selectively connecting the fifth rotational element and the ninth rotational element; 
 a second clutch selectively connecting the seventh rotational element and the eighth rotational element; 
 a third clutch selectively connecting the eleventh rotational element and the fourteenth rotational element; 
 a fourth clutch selectively connecting the sixth rotational element and the eighth rotational element; 
 a first brake arranged between the ninth rotational element and the transmission housing; and 
 a second brake arranged between the twelfth rotational element and the transmission housing. 
 
     
     
       16. The planetary gear train of  claim 13 , further comprising:
 a first clutch selectively connecting the fifth rotational element and the ninth rotational element; 
 a second clutch selectively connecting the seventh rotational element and the ninth rotational element; 
 a third clutch selectively connecting the eleventh rotational element and the fourteenth rotational element; 
 a fourth clutch selectively connecting the sixth rotational element and the eighth rotational element; 
 a first brake arranged between the ninth rotational element and the transmission housing; and 
 a second brake arranged between the twelfth rotational element and the transmission housing. 
 
     
     
       17. The planetary gear train of  claim 13 , further comprising:
 a first clutch selectively connecting the fifth rotational element and the ninth rotational element; 
 a second clutch selectively connecting the eighth rotational element and the ninth rotational element; 
 a third clutch selectively connecting the eleventh rotational element and the fourteenth rotational element; 
 a fourth clutch selectively connecting the sixth rotational element and the eighth rotational element; 
 a first brake arranged between the ninth rotational element and the transmission housing; and 
 a second brake arranged between the twelfth rotational element and the transmission housing. 
 
     
     
       18. The planetary gear train of  claim 14 , further comprising:
 a first clutch selectively connecting the fifth rotational element and the ninth rotational element; 
 a second clutch selectively connecting the seventh rotational element and the eighth rotational element; 
 a third clutch selectively connecting the third rotational element and the thirteenth rotational element; 
 a fourth clutch selectively connecting the sixth rotational element and the eighth rotational element; 
 a first brake arranged between the ninth rotational element and the transmission housing; and 
 a second brake arranged between the twelfth rotational element and the transmission housing. 
 
     
     
       19. The planetary gear train of  claim 14 , further comprising:
 a first clutch selectively connecting the fifth rotational element and the ninth rotational element; 
 a second clutch selectively connecting the seventh rotational element and the ninth rotational element; 
 a third clutch selectively connecting the third rotational element and the thirteenth rotational element; 
 a fourth clutch selectively connecting the sixth rotational element and the eighth rotational element; 
 a first brake arranged between the ninth rotational element and the transmission housing; and 
 a second brake arranged between the twelfth rotational element and the transmission housing. 
 
     
     
       20. The planetary gear train of  claim 14 , further comprising:
 a first clutch selectively connecting the fifth rotational element and the ninth rotational element; 
 a second clutch selectively connecting the eighth rotational element and the ninth rotational element; 
 a third clutch selectively connecting the third rotational element and the thirteenth rotational element; 
 a fourth clutch selectively connecting the sixth rotational element and the eighth rotational element; 
 a first brake arranged between the ninth rotational element and the transmission housing; and 
 a second brake arranged between the twelfth rotational element and the transmission housing.